It would be cool to publish the 'Trending petitions' history as open data

[henryhadlow]

Proposal:

• Add journaling per petition to record the signature count hourly
• To keep it performant you could have daily rows with 24 columns, one for each hour
• The signing rate could be easily calculated, just the difference between one hour's count and the previous count
• We could then add this data to the existing json for each petition (eg https://petition.parliament.uk/petitions/124333.json)

This would let people see the signing history of petitions and make mashups where you could see trending petitions against events in the news